Here's
something I bet you didn't know: you can stimulate brain activity by shining
light ... into your ears!

Bright light stimulation was found to increase activity in brain
areas related to processing of visual sensory information and tactile
stimuli. The findings are the first ever published scientific article
about functional modulation of the brain with bright light delivered
to the brain through the ears. [...]

"The research results confirm that it is possible to influence
brain functions with bright light delivered directly to the brain through
the ear," says researcher TuomoStarck from the Oulu University
Hospital. "The group that received bright light demonstrated in
the analysis significant increase in neural network activity especially
in brain areas connected with visual perception."

"There is earlier proof of the existence of photosensitive
proteins, such as opsins, in the brain. This study confirms light-responsiveness
of the brain itself, and that bright light given through the ear canal
is a very viable method for influencing mood," says Professor and
Leading Senior Physician Timo Takala from Oulu Deaconess Institute.

This is highly implausible. What light penetrates the ear drum will only be met with the solid bone encasing the middle ear. Even if any light were still able to penetrate the bone, look up any anatomical drawing of the human skull and you'll see that the inner ears lie beneath the lowest point of the temporal lobe. In other words, the light wouldn't even be hitting the brain. Considering all of the above, even if the light somehow does manage to reach the brain, the existence of photoreceptive cells in the brain that can be stimulated by direct light exposure is questionable.

In addition, there are serious conflicts of interest for a number of authors of the study. The 2nd and 3rd authors are CEOs of a company selling a (very expensive) device that claims that by using its product to shine LED lights into your ears, you can treat Seasonal Affective Disorder (SAD). 2 other authors (including Takala) are shareholders of this company, and the lead author is a live-in partner of an employee of the company. You'll also notice that these authors have a hand in every single study making similar claims. In other words, they have no independent evidence supporting their claims.

I'm an auduologist and I shine lights into peoples' ears for a living. Perhaps I should start charging an additional fee for "mood influencing properties".